1. Field of the Invention
The invention relates to apparatus and methods for retrieving and playing information from disks, cassettes, or other information storage units. More specifically, the invention relates to a replay device having independent user locations for accessing the stored information and presenting the information accessed.
2. Description of the Prior Art
The technique of storing information on a disk, cassette or other storage unit has long been known. For example, a musical selection may be recorded in a groove on a vinyl disk and replayed by conventional phonographic techniques. Other examples include cassettes, floppy disks, or diskettes, and hard disks for storing digital data in a magnetic form which may be read with appropriate magnetic sensors. More recently, optical and capacitive (CED) disks have been developed which store information in a form which can be retrieved optically or capacitively. The optical disks are sometimes referred to as laser disks, because they may be read using light emitted by a laser.
Because of the information storage capacity of optical and CED disks, it has become feasible to store both audio and video information on a disk, and such a disk will be referred to herein as a video disk. As a result, a musical selection, for example, may be recorded together with a video script or program on a video disk, and the two may be replayed together for entertainment, commercial or educational purposes. It is also known to provide such information on magnetic tapes as, for example, in a cassette, even though each tape is limited to a certain amount of information, typically 45 musical selections.
One type of prior art disk player for playing a plurality of disks is disclosed in U.S. Pat. No. 4,387,452, issued to Bricot et al. In this device, a number of disks are stacked, and an optical playing device is inserted between the disks for accessing the stored information.
Another prior art disk player is disclosed in U.S. Pat. No. 4,286,790, issued to Siryj et al. In this device, a number of disks are stored in a rack. A changer is movable along the rack to remove disks from the rack and insert them in the same orientation into an optical reader. As a result, the number of disks which can be accessed is increased.
It would be advantageous, however, to provide a player which could play more than one disk or cassette at a time or in sequence, yet could select from a larger number of disks or cassettes in a storage rack. Such a disk player would reduce or eliminate the delay between the playing of disks, by permitting the selection and retrieval of one disk while another is played. Such a disk player would also preferably play selectively from either side of each disk and would randomly access the information within each side of each disk, to increase the amount of information readily accessible. It would further be advantageous to provide such a player in a system with independent user stations for independently selecting the information to be accessed and played and for receiving the information played. Furthermore, it would be advantageous to provide such a system capable of playing video disks. The system could further be an interactive library or information retrieval system in which a user's respoonse determines which information is accessed.